A touch sensor has been known as an interface for a user to input information to a display device. When the touch sensor is installed on a screen of the display device, the user can input information to the display device and operate an application by touching an input button, an icon, and the like displayed on the screen. Japanese Patent Application Publication No. 2013-242699, for example, discloses a touch panel capable of uniquely determining touched coordinates.
In the touch panel described in Japanese Patent Application Publication No. 2013-242699, a self-capacitance system and a mutual capacitance system are adopted in combination to uniquely determine the touched coordinates. The touch panel is manufactured separately from a display device, and is used while overlapping the display device.